Electromechanical lock devices that include an electrically co-acting or controlled release mechanism for manoeuvring a lock cylinder are known to the art. For example, U.S. Pat. No. 5,839,307 describes an electromechanical cylinder lock that includes outer lock housing and a core which is rotatable in the lock housing and which is controlled by double lock elements, The core includes a plurality of electromechanical lock elements that include slots which receive a side bar in a non-latched position. A magnetic core rotates the electromechanical latching elements to a desired position in relation to the side bar so as to enable the drum to be rotated.
One drawback with this known lock device is that it does not include mechanical resetting of the latch elements. This means that the latch elements will remain in a non-latching state if the lock is activated during manoeuvring of the lock, thereby detracting from the security of the lock. This can be the result if the key-mounted battery that powers the latching mechanism is removed.
A cylinder lock of the kind given in the introduction is described in Swedish patent specification SE 9904771-4. This patent specification describes the manner in which a linearly movable finger (see FIG. 1) rotates an actuator under the control of a key-carried code surface. The actuator, in turn, allows, or prevents, movement of a side bar.
This solution is encumbered with several drawbacks. Firstly, it is relatively space consuming. Secondly, movement of the finger is code-dependent, in other words it is necessary to include a suitable code surface. This solution will not work if the key lacks such a code surface.
The European patent publication EP 1134335A2 describes a lock device of the type given in the introduction, in which a latching mechanism includes a linearly movable part. Consequently, this solution is also space consuming and code dependent.